Electrolytic Reduction: For highly electropositive metals (Na, Mg, Al). (e.g., Hall-Heroult process for Al).

Thermite Process: $Fe_2O_3 + 2Al \to Al_2O_3 + 2Fe$. For metals like Cr, Mn.

Ellingham Diagram: Plots $\Delta G^\circ$ vs T for formation of oxides. Used to predict feasibility of reduction. A metal can reduce the oxide of another metal if its $\Delta G^\circ$ line is below the other metal's line at that temperature.

Refining:

Distillation: For low boiling metals (Zn, Cd, Hg).
Liquation: For low melting metals (Sn, Pb, Bi).
Electrolytic Refining: For Cu, Ag, Au, Zn, Ni. Impure metal as anode, pure metal as cathode.
Zone Refining: For ultra-pure semiconductors (Ge, Si, Ga, In). Impurities more soluble in melt than solid.
Vapour Phase Refining:
- Mond Process: For Ni ($Ni + 4CO \xrightarrow{330-350K} Ni(CO)_4 \xrightarrow{450-470K} Ni + 4CO$).
- Van Arkel Method: For Zr, Ti ($Zr + 2I_2 \xrightarrow{870K} ZrI_4 \xrightarrow{2075K} Zr + 2I_2$).
Chromatographic Methods: For highly pure elements.

Organic Chemistry - Advanced Concepts & Reactions

1. General Organic Chemistry (GOC)

Nomenclature (IUPAC): Master rules for complex structures, polyfunctional groups, cyclic compounds, bicyclic compounds, spiro compounds.
Isomerism:
- Structural: Chain, Position, Functional, Metamerism, Tautomerism (Keto-enol tautomerism: $\alpha$-hydrogens required, enol form is stabilized by conjugation/H-bonding).
- Stereoisomerism:
  - Geometrical (cis-trans/E-Z): For alkenes ($R_1R_2C=CR_3R_4$) and cyclic compounds. E-Z system for more complex cases (priorities based on atomic number).
  - Optical:
    - Chirality: Molecule non-superimposable on its mirror image. Usually due to chiral carbon (4 different groups).
    - Enantiomers: Stereoisomers that are non-superimposable mirror images. Rotate plane-polarized light equally but in opposite directions (dextro- (+), levo- (-)).
    - Diastereomers: Stereoisomers that are not mirror images. Different physical properties.
    - Meso Compounds: Contain chiral centers but are optically inactive due to internal plane of symmetry.
    - Racemic Mixture: Equimolar mixture of enantiomers, optically inactive. Resolution: Separation of racemic mixture.
    - Specific Rotation: $[\alpha]_D^T = \frac{\alpha}{l \times c}$ (observed rotation / (length of tube x concentration)).
    - Configuration: R/S system (Cahn-Ingold-Prelog rules).
    - Walden Inversion: Inversion of configuration at chiral center during $S_N2$ reaction.
Electronic Effects (Influence on Reactivity & Stability):
- Inductive Effect (I): Permanent, through $\sigma$-bonds. Decreases with distance. (+I: alkyl groups; -I: -NO$_2$, -CN, -COOH, halogens).
- Resonance / Mesomeric Effect (R/M): Permanent, through $\pi$-bonds. Delocalization of $\pi$ electrons/lone pairs. (+M: -OH, -OR, -NH$_2$, -Cl (lone pair donation); -M: -NO$_2$, -CN, -CHO, -COOH (electron withdrawal)).
- Hyperconjugation: Delocalization of $\sigma$ electrons (C-H bond) into adjacent empty p-orbital or $\pi$-orbital. "No-bond resonance". Stabilizes carb